A phenol resin molding material is excellent in heat resistance and dimensional stability and is therefore used as a substitute for metal in various fields. In the automobile field, the material of various components has been changed to a resin due to new requirements such as size reduction, weight saving and cost reduction. In particular, a conventional pulley made exclusively of metal has been replaced by a resin pulley and pulleys having various shapes have been molded. The resin pulley had a drawback that, when used in the state where there is dust between the pulley and a rubber belt, the surface in contact with the belt is likely to be abraded and the resin pulley is inferior in durability as compared with a conventional metal pulley. Therefore, there has been proposed a resin pulley in which abrasion resistance and heat cycle resistance are improved by mixing the phenol resin with a natural silica powder having an average particle size of 20 to 150 μm (for an example, see Japanese Unexamined Patent Publication (Kokai) No. 2002-201335).
Although the dust resistance is improved, the resin pulley has a problem that a large load is applied to production facilities such as molds and molding machines because the silica powder has a large particle size to provide excellent abrasion resistance, resulting in a short life of the facilities. Thus, a further improvement has been required.